Halloysite nanotubes: prospects and challenges of their use as additives and carriers – A focused review

Abstract

There is increasing research interest in potential applications of halloysite as fillers for polymer composites, controlled drug delivery, carriers for the supply and sustained release of active agents for anticorrosion coatings, in nanoreactors or nanotemplates, and for the uptake of contaminants or pollutants and support for catalysts. In this review, recent findings in terms of the prospects and challenges of using halloysite nanotubes (HNTs) in different polymeric matrices targeting a range of old and new applications are discussed and evaluated. The compositions include chitosan/halloysite membranes as bone-tissue scaffolds, polylactic acid (PLA)/halloysite membranes for food-packaging applications and their antimicrobial activities, instrumented impact properties of epoxy/halloysite nanocomposites and the role of halloysite in the self-healing of epoxy composites, polyacryronitrile (PAN)/halloysite membranes for use in water filtration as well as a review of some recent applications of halloysite/alginate beads in the adsorption of contaminants such as lead.

Thin-walled nanoscrolls by multi-step intercalation from tubular halloysite-10 Å and its rearrangement upon peroxide treatment

“…Zn/TiO 2 oxides deposited on the halloysite surface represent anti-microbial properties [5], and can be used as photocatalysts for the removal of organic (and with additional surface treatment NO x ) pollutants [14]. The tubular morphology enables its use as a container for corrosion inhibitors [3,5]. The adsorption properties and biological activities of the so-called spheroidal halloysites differ significantly from those of the tubular ones, due to their significantly different morphology.…”

“…With the preparation of halloysite nanocomposites/hybrids novel types of materials with desirable properties can be generated. Zn/TiO 2 oxides deposited on the halloysite surface represent anti-microbial properties [5], and can be used as photocatalysts for the removal of organic (and with additional surface treatment NO x ) pollutants [14]. The tubular morphology enables its use as a container for corrosion inhibitors [3,5].…”

“…The tubular morphology of halloysite with nano-sized diameter, the corresponding one-dimensional mesoor macroporosity offer various practical applications as catalysts, filling or packing materials, nanocontainers or nano-sized chemical reactors [1][2][3][4][5] and adsorbents [5]. Optimization of surface properties are of importance in the preparation of polymer hybrids [6], functional materials and intelligent surface coatings [7][8][9][10], biomimetric nanoreactor [3,11], as well as catalyst supports [12,13].…”

Effect of different compatibilizers on environmentally friendly composites from poly(lactic acid) and diatomaceous earth

“…HNTs, at 1–7 wt%, have also been successfully incorporated into polyethylene terephthalate as nanocontainers of antimicrobial agents for active packaging . PLA nanocomposites with 5 wt% HNTs showed an increase of 43% in the tensile strength of PLA due to the formation of hydrogen bonds between the hydroxyl groups of PLA chains and the outer‐surface siloxane groups of the HNTs . Bendahou et al used zeolites as nanofillers in a PLA matrix, obtaining important improvements in barrier and antimicrobial characteristics as well as improved mechanical behaviour (high modulus and high tensile strength).…”

“…15 PLA nanocomposites with 5 wt% HNTs showed an increase of 43% in the tensile strength of PLA due to the formation of hydrogen bonds between the hydroxyl groups of PLA chains and the outer-surface siloxane groups of the HNTs. 16 Bendahou et al 17 used zeolites as nanofillers in a PLA matrix, obtaining important improvements in barrier and antimicrobial characteristics as well as improved mechanical behaviour (high modulus and high tensile strength). PLA/nanoclay composites are interesting materials for active packaging with environmentally friendly performance, as reported by Lorite et al 18 Jampilek and Kráľová 4 suggested that bio-nanocomposites, using SiO 2 , offer good packaging properties due to their fine dispersion, increased mechanical strength, reduced gas permeability and improved water resistance.…”